Table of contents monday, September 9, 1: 30pm-4: 00pm modular Multi-Level Converters, hvdc, and dc grids I 3
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- Bu səhifədəki naviqasiya:
- Wide Bandgap Applications: SiC
- Wednesday, September 21, 1:30PM-3:10PM Modeling and Control of Alternative Energy Applications
- Utility Applications IV
- Modeling, Analysis, and Control of Grid-Connected Converters III
| 11:20AM Permanent Magnet Temperature Estimation in PMSM Using Low Cost Hall Effect Sensors [#183]
Daniel Fernandez, Doosoo Hyun, Yonghyun Park, David Reigosa, Sang Bin Lee, Dong Myung Lee and Fernando Briz, University of Oviedo, Spain; Dept. of Elec. Eng.,Korea University, Seoul, Korea (South); Dept. of Elec. Eng., Hongik University, Seoul, Korea (South) Knowledge of the permanent magnet (PM) temperature in PM synchronous machines (PMSMs) is of great importance both for control and monitoring purposes. Increase in PM temperature during motor operation can degrade the magnetic flux strength and consequently the machine torque production capability, also can cause irreversible demagnetization of the PM. Direct measurement of the PM temperature is not viable in practice, due to both cost and reliability issues. Indirect PM temperature estimation methods recently studied can require knowledge of thermal or electrical model parameters or can have undesired effects on motor operation. In this paper, the feasibility of using low cost hall-effect sensors for PM temperature estimation is investigated. Hall sensors are present for detecting the initial position of the rotor in majority of PMSM applications for which incremental encoders are used for control. The proposed method can therefore be implemented with low or no additional cost. Experimental results n two IPMSMs show that the method is capable of providing non- invasive estimation of the PM temperature without a priori motor parameter information for monitoring and protection against excessive increase in temperature. 11:45AM Analysis and Suppression of Zero Sequence Circulating Current in Open Winding Permanent Magnet Synchronous Machine Drives with Common DC Bus [#448]
In this paper, the zero sequence circulating current in open winding (OW) permanent magnet synchronous machine (OW-PMSM) drives with common DC bus is systematically analysed for the first time. It is revealed that the zero sequence circulating current is affected by zero sequence back electromotive force (EMF), cross coupling voltages in zero sequence, from the machine side, pulse width modulation (PWM) induced zero sequence voltage and inverter nonlinearity, from the inverter side. Particularly, the influences from the cross coupling voltages in zero sequence and parasitic effect of inverter nonlinearity are investigated for the first time in this paper. Then the synthetic model of the equivalent zero sequence circuit is proposed as well. Each cause is studied independently via analytical modelling, finite element analysis and experiments. Meanwhile, to tackle this issue, the relevant suppression strategy using frequency adaptive proportional resonant controller is presented and tested on the 3kW OW-PMSM platform. Wide Bandgap Applications: SiC Wednesday, September 21, 10:30AM-12:10PM, Room: 202C, Chair: Ruxi Wang, Jerry Hudgins 10:30AM A Compact 100-A, 850-V, Silicon Carbide Solid-State DC Circuit Breaker [#230] Damian Urciuoli, Oladimeji Ibitayo, Gail Koebke, Gregory Ovrebo and Ronald Green, U.S. Army Research Laboratory, United States A 100-A, 850-V, solid-state circuit breaker (SSCB)having silicon carbide transistors and diodes was developed. The SSCB conducts 100 A continuously with air cooling in a 32 square-centimeter footprint. It is normally off and unidirectionally blocking, and has a configurable trip response allowing a range of overcurrent transients to be conducted, while maintaining a fast trip response at its fault-current limit. The SSCB also provides remote trip, status output, and reset functions. The time-versus-current trip response of the SSCB was characterized at 25, 50, and 75 degrees Celsius baseplate temperatures using pulsed currents with ramp rates of over 70 amps per microsecond. Saw-tooth-shaped current pulse widths of less than 5 microseconds, with amplitudes of greater than 200 A, were demonstrated. 10:55AM Matrix Converter with Sinusoidal Input-Output Filter and Filter Downsizing Using SiC Devices [#446]
The matrix converter is an AC-to-AC direct power conversion system that can generate variable voltage variable frequency output. There is a topology of Matrix converter having sinusoidal waveforms using output LC filter. It enabled that to provide lower EMI, lower common-mode current, and lower shaft voltage. However, there are some problems that filter size become bulky because of the restriction of switching speed using conventional power module, Silicon IGBT. Downsizing of input- output filter can be realized by employing SiC power devices since they are associated with low losses and can be operated at high frequency. In this paper, the use of SiC power devices in matrix converters is studied and its effect in reducing the size of the input and output filter is verified. A prototype was built for evaluations and the results are presented. 11:20AM H-Bridge Building Block with SiC Power MOSFETs for Pulsed Power Application [#1619]
This paper presents a H-bridge building block with 1700V SiC MOSFET for a pulsed power application to achieve both high voltage, high current and high switching frequency capability. Both power module level and system level stray inductance is minimized to better utilize the SiC high switching speed capability. Meanwhile, since the large pulsed energy is required to drive the pulsed load, voltage sensing for active DC link voltage compensation is proposed and designed. 11:45AM Three-phase active front-end rectifier efficiency improvement with silicon carbide power semiconductor devices [#983]
This paper investigates SiC power semiconductor devices in a three-phase active front-end Boost PWM rectifier for power conversion efficiency improvement. Different from Si IGBT based Boost PFC rectifier, the SiC MOSFET based Boost PFC rectifier can achieve the synchronous rectification by MOSFET channel reverse conduction for efficiency improvement. The operation principle difference of three-phase active front-end Boost PWM rectifier with SiC MOSFET and Si IGBT is introduced. The switching characterizations of 1.2kV SiC MOSFET are provided. 5kW 380VAC input, 800VDC output three-phase active front-end Boost PWM rectifier prototype is built in lab to evaluate the efficiency advantage with SiC device. All SiC power semiconductor devices based circuit achieves about 1.2 percent more efficient compared with all Si devices, and around 0.5 percent more efficient than Si IGBT and SiC diode hybrid device pair for the three-phase Boost PWM rectifier due to low switching loss of 1.2kV SiC MOSFET and reduced conduction loss from the synchronous rectification operation for 1.2kV SiC MOSFET. LED Drivers Wednesday, September 21, 10:30AM-12:10PM, Room: 102A, Chair: Huai Wang, David Perreault 10:30AM Precise and Full-Range Dimming Control for An Off-Line Single-Inductor-Multiple-Output LED Driver [#752] Sinan Li, Yue Guo, Ting Leung Albert Lee, Siew Chong Tan and Shu Yuen Ron Hui, The University of Hong Kong, Hong Kong In this paper, PWM dimming is studied for an off-line single-inductor-multiple-output (SIMO) LED driver at the string level (i.e., only one power channel is active) and at the system level (i.e., all power channels are active). The issues of employing PWM dimming over a SIMO LED driver are investigated and the corresponding solutions are proposed. With the proposed dimming technique, a SIMO LED driver can achieve a high dimming precision and a full dimming range for each power channel. The proposed PWM dimming method has been practically verified with a 25 W off-line SIMO LED driver prototype. 10:55AM Design and Implementation of a Retrofit LED Lamp for AC Mains and Ballasts [#155]
In this paper, the design and implementation of a retrofit LED lamp for AC mains and ballasts is proposed. The proposed driver contains a simple technique to deal with the different kinds of sources between high frequency power from electronic ballasts and low frequency power from AC grid and electromagnetic ballasts. With this technology, the fluorescent lamp can be replaced with the proposed LED lamp without exchanging the existed lighting fixtures and the circuitry does not need to be rewired, which will decrease the cost of change the entire system. The operating principles of the proposed LED lamp, the design consideration, and the key parameters will be discussed. Finally, a hardware prototype of a 22W retrofit LED lamp is built to verify the feasibility of the proposed method. 11:20AM A Current Compensator for Mitigating the Influence of Long Cable Inductance between the LED Driver and the Light Source [#635]
It is sometimes unavoidable to use a long cable to connect the light source to the driver when they are placed far apart in large scale LED lighting installation. Since LED driver typically delivers pulse-width-modulated current pulses, the long cable inductance will delay the rate of rise of the current pulses and will also cause negative off-state voltage across the light source, reducing luminous output and vitiating the life expectancy of the light source. This paper will present a current compensator, which can mitigate the distortion of the current pulses caused by the long cable. The concept is based on recycling the energy stored in the cable at the end of a current pulse and then driving the light source synchronously with the driver at the beginning of the next current pulse. A prototype for a 12V, 4.5A LED driver has been built and evaluated. Topological states, operations and experimental results will be given. 11:45AM Investigation into the Use of Single Inductor for Driving Multiple Series-Connected LED Channels [#883]
This paper provides an investigation into the use of single inductor for driving N series-connected LED channels. For each LED channel, there is a parallel- connected switch controlling the LED channel current and also charging the inductor. Compared with the conventional structure having (N+1) switches and all LED channels connected in parallel, the proposed structure has the merits of 1) requiring only N switches, 2) being insensitive to the duration of the transition switching from one channel to another, and 3) allowing all channels to be driven concurrently in every switching cycle. Mathematical analysis on the topological operations will be discussed. Experimental results of a two- channel system, demonstrating the concept, are presented. Wednesday, September 21, 1:30PM-3:10PM Modeling and Control of Alternative Energy Applications Wednesday, September 21, 1:30PM-3:10PM, Room: 203C, Chair: Eduard Muljadi, Akshay Kumar Rathore
1:30PM Using Markov Switching Model for Solar Irradiance Forecasting in Remote Microgrids [#1096] Ayush Shakya, Semhar Michael, Christopher Saunders, Douglas Armstrong, Prakash Pandey, Santosh Chalise and Reinaldo Tonkoski, South Dakota State University, United States In recent years, there has been rapid growth of Photovoltaic (PV) system integration into diesel-based remote microgrids to reduce the diesel fuel consumption. However, due to low correlation of PV power availability with the load as well as uncertainty and variability of the PV power, the benefits of the integration have not been achieved properly. A large energy reserve is required to compensate the fluctuation and improve reliability, which leads to increased operational cost. Solar irradiance forecasting helps to reduce the reserve requirement and improve the PV energy utilization. In this paper, a novel solar irradiance forecasting using Markov Switching Model is proposed for remote microgrids. This forecasting method uses locally available historical irradiance data of the microgrid location to predict day-ahead irradiance. The case study for validating this method for Brookings, SD resulted in Root Mean Square Error (RMSE) of 99.6 W/m^2 for 2008 and 106.8 W/m^2 for 2011. 1:55PM Determining Maximum MPP-Tracking Sampling Frequency for Input-Voltage-Controlled PV-Interfacing Converter [#392]
A maximum-power-point tracking (MPPT) algorithm is essential in all controllers of solar power electronic converters due to the nonlinear current-voltage characteristics of a photovoltaic generator. One of the most widely utilized algorithms are perturbative MPPT techniques such as perturb and observe and incremental conductance methods due to their simple implementation with relatively good tracking performance. However, in order to optimize the performance of such algorithms, the design parameters - sampling frequency and perturbation step size - need to be designed in respect to interfaced power electronic converter. Recent studies have provided state-of-art MPP-tracking design rules for single and two-stage grid-connected PV systems. Unfortunately, the analysis of those studies does not provide analytical results for PV power transient response under feedback-controlled converters. This paper provides reduced-order transfer functions for the converters equipped with either I-type or PID-type controllers in order to approximate the maximum sampling or perturbation frequency for MPP-tracking algorithms. The analysis reveals the factors affecting the transient behavior similarly as in open-loop converter providing valuable tools for optimizing MPP-tracking perturbation frequency design. 2:20PM Real-time Emulation of a Pressure Retarded Osmosis Power Generation System [#703]
Power production by conversion of salt gradient energy (osmotic power production) has potential for global commercialization. Research on the net- power output and plant configuration provide viable methods for efficient plant operation. In this paper, a novel equivalent electric-circuit model of the pressure retarded osmosis process (PRO) is described and, is used to develop a power hardware-in-the-loop (PHIL) emulator to represent the osmotic power plant which includes impulse turbine and synchronous generator for supplying power to offgrid or isolated loads. The response of the hydraulic, mechanical and electrical components of the system is observed given changes in the source flow-rate and electrical loading. The proposed PHIL emulator provides insight into the operational dynamics and behavior of the PRO system. The proposed real-time emulator is a powerful tool which can advance research and development of pressure retarded osmotic power generation system. Simulation and experimental results are presented in the paper to validate the operation of the proposed PHIL PRO emulator. 2:45PM Efficient FCTV Provision considering DWT and DWPT-based Noise Suppression for Overcoming the Noise-Induced Voltage Loss in PEM Fuel Cell [#1585]
This approach gives insight to the design and implementation of the noise suppression based on the wavelet transform (WT) for efficient FCTV signal provision. The most important thing in this approach is to show the comparative analyses on noise suppression between two transforms, such as the discrete wavelet transform (DWT) and discrete wavelet packet transform (DWPT). With an identical mother wavelet of Daubechies db3, the multi-resolution analysis (MRA) -based decomposition and reconstruction processes for reducing the noise- induced voltage loss are basically done in the DWT and DWPT. The marked difference between two transforms is the MRA-based decomposition/reconstruction ability of high frequency component related to the sensing of noisy. For reference, this approach considered two noise suppression techniques such as hard- and soft-thresholdings and checked signal-to-noise ratio (SNR) values for clear evaluation of all comparative analyses. From these results, it is capable of suggesting three conclusions. First, the performance on noise suppression of the DWPT is superior to that of the DWT. Second, the noise-induced voltage loss is more suppressed at soft-thresholding technique when compared to hard- thresholding technique irrespective of the DWT and DWPT. Last, the optimal decomposition/reconstruction levels that have the maximum SNR values are respectively determined in hard- and soft-thresholding techniques. Our definite suggestions sufficiently enable us to achieve an optimal solution for efficient FCTV provision. This approach has been extensively verified by experimental results of the FCTV using a single cell. Utility Applications IV Wednesday, September 21, 1:30PM-3:10PM, Room: 202A, Chair: Fariba Fateh, Yipeng Song 1:30PM Field Test Results for a 12.47 kV 3-Phase 1 MVA Power Router [#1351] Rajendra Prasad Kandula, Hao Chen, Anish Prasai, Frank Lambert, Joe Schatz, Thomas Powell, Timothy Heidel, Colin Schauder and Deepak Divan, Georgia institute of technology, United States; Varentec, United States; Southerncompany, United States; Georgia Power, United States; Advanced Research Projects Agency-Energy, United States; Booz Allen Hamilton, United States The increasing load, increasing level of penetration of renewable energy and limited investment in transmission infrastructure have significantly increased the need for a smart, dynamically controllable grid. The authors have previously proposed a power flow control device to maximize asset utilization, improve reliability, and reduce congestion. The proposed power router is realized by augmenting an LTC-like transformer with a fractionally-rated direct AC converter. The paper will discuss the field test results of a 12.47 kV, 1 MVA three-phase power router installed on a 12.47 kV feeder. Description of the test feeder, the power router configuration, protection peripherals and initial test results are presented. The test results verify the power router design to address key design challenges associated with utility-grade equipment that includes requirement for high reliability and availability, long life in excess of 20 years with limited or no maintenance schedule, rugged and often harsh operating environment, high BIL ratings and high fault-handling capabilities 1:55PM DC Capacitor Voltage Balancing Control for Delta-Connected Cascaded H-Bridge STATCOM Considering the Unbalanced Grid and Load Conditions [#991]
In this paper, a comprehensive control scheme for a delta-connected cascaded h-bridge (CHB) converter based static synchronous compensator(STATCOM) is presented, especially focusing on improving dynamic performance by novel feedforward control method. The method can conspicuously improve the dynamics of circulating current regulation of delta connected CHB STATCOM especially under grid fault condition as well as load unbalance without excessive DC cell capacitor voltage fluctuation. The full scaled simulation results and the down scaled experimental results verify that stable operation is guaranteed for both emulated grid and load unbalance conditions. 2:20PM Advanced Grid Simulator for Multi-Megawatt Power Converter Testing and Certification [#1054]
Grid integration testing of inverter-coupled renewable energy technologies is an essential step in the qualification of renewable energy and energy storage systems to ensure the stability of the power system. New types of devices must be thoroughly tested and validated for compliance with relevant grid codes and interconnection requirements. For this purpose, highly specialized custom-made testing equipment is needed to emulate various types of realistic grid conditions that are required by certification bodies or for research purposes. For testing multi-megawatt converters, a high power grid simulator capable of creating controlled grid conditions and meeting both power quality and dynamic characteristics is needed. This paper describes the new grid simulator concept based on ABB's medium voltage ACS6000 drive technology that utilizes advanced modulation and control techniques to create an unique testing platform for various multi-megawatt power converter systems. Its performance is demonstrated utilizing the test results obtained during commissioning activities at the National Renewable Energy Laboratory in Colorado, USA. 2:45PM Experimental Verification of Capacitance Reduction in MMC-Based STATCOM [#1264]
This paper proposes capacitance reduction in modular multilevel converter (MMC) based static synchronous compensator (STATCOM). The MMC-based STATCOM consists of several series connected single-phase STATCOM; therefore, the required capacitance to achieve a constant dc voltage is comparatively high. The basic concept of the capacitance reduction and control principle have been proposed in single-stage STATCOM. This paper extents them to MMC configuration. A control method including capacitor peak voltage based control and voltage balancing control is proposed. The control was demonstrated in a fabricated small-scale setup of 3-cascaded single-phase STATCOM, and waveforms in stead-state and transient are shown. By applying the proposed control technique, the peak voltage was confirmed to be almost constant while the current set-point is changed in step, and a good voltage balancing in dc-side capacitors of each cell was also confirmed. Modeling, Analysis, and Control of Grid-Connected Converters III Wednesday, September 21, 1:30PM-3:10PM, Room: 202D, Chair: Ali Davoudi, Edison da Silva 1:30PM A Comparative Study of Methods for Estimating Virtual Flux at the Point of Common Coupling in Grid Connected Voltage Source Converters With LCL Filter [#68] Nurul Fazlin Roslan, Jon Are Suul, Alvaro Luna, Joan Rocabert, Ignacio Candela and Pedro Rodriguez, Universitat Politecnica de Catalunya, Terrassa, Spain; SINTEF Energy Research, Trondheim, Norway; Abengoa Research Centre, Seville, Spain Grid connected Voltage Source Converters (VSCs) with LCL filters usually have voltage measurements at the filter capacitors, while it can be important to control the active or reactive power injection at the grid-side of the LCL filter, for instance at a Point of Common Coupling (PCC). Synchronization to the PCC voltage can be obtained by Virtual Flux (VF) estimation, which can also allow for voltage sensor-less operation of VSCs. This paper is presenting a comparative evaluation of methods for estimating the VF at the PCC, considering a VSC connected to the grid through an LCL filter with a Proportional Resonant (PR) controller as the inner current control loop. The VF estimation is achieved by using frequency adaptive dual SOGI-QSGs (DSOGI-VF). The Frequency Locked Loop (FLL) is used in order to keep the positive and negative sequence (PNS) VF estimation inherently frequency adaptive. Three different methods are considered for obtaining the capacitor current needed for estimating the VF at the grid side of the LCL filter which are based on fully estimation by using the voltage sensor-less method, by estimating the capacitor current from the measured voltage or by using additional capacitor current sensors. The results have been compared and validated by simulation studies.
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